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A few weeks ago we discovered that the performance of our Windows 2012 guest on KVM hypervisors was very bad and it was caused by the "Performance per Watt (DAPC)" profile in the BIOS of our Dell m620 servers. After that, I got curious and started to test with other systems: Linux guests and bare metal. According to the Dell BIOS Performance and Power Tuning documentation, the difference between the performance per watt (dapc) and performance per watt (os) profile should be only a few percent:

Icinga published some Ansible examples on their github, but I didn't find them very useful. It's most of the time only a basic installation and you still have to execute manual steps to finish the installation.

If you run Windows 2012 guests on RHEV or Ovirt (or probably any KVM based hypervisor) and notice performance is lower than expected, take a look at the power management in the BIOS of your servers. After lot's of test benchmarks with mixed results with Windows 2012 guests on RHEV with Dell m620 blades, we finally discovered our performance problems were caused by the system profile "Performance Per Watt (DAPC-System)" in the BIOS. Changing this profile to "Performance Per Watt (OS)" almost doubled the performance for some CPU intensive tasks in our case. Power usage of a (mostly idle) dual socket blade increases with 30-50 Watts when you change this. Used servers in production are using already more power and I guess the difference will be less there.

I found lot's of examples to take screenshots in I3, but most of them require additional scripts or will always overwrite the same temp file. So I've been testing a bit to make it easier. Put this in your .i3/config to take Gnome style screenshots in a png in ~/Pictures. Mod+x selects a rectangle on the screen or mod+y takes the entire screen contents.